Re-sealable plastic bags are widely used to preserve food. Such bags are referred to as “re-sealable plastic bags” and typically have a mating male rib or bead and female channel extending along the opening of the bag that form an airtight closure when pressed together along the length of the bag seal. Naito, U.S. Pat. No. RE 28,969 discloses an example of an airtight profile closure used in the ZIPLOC® storage bag. The airtight closure is typically formed as an integral part of the bag and allows products stored in the bag to be easily removed and re-stored.
Re-sealable plastic bags help preserve food by limiting the amount of oxidizing air to which the food is exposed. However, since ordinary re-sealable bags expose the food inside to the air entrapped in the bags, it is desirable to evacuate or vacuum seal the bag. In sealing such re-sealable bags, users typically manually squeeze air from the bag while simultaneously closing the opening. Unfortunately, some air remains in the bag, and air can re-enter and become trapped in the bag during the initial sealing or re-sealing process.
Others have attempted to overcome problems associated with manually sealing re-sealable bags by modifying the closure, providing specially designed bags, or providing bag attachments for evacuating the bag.
Kugler, U.S. Pat. No. 3,339,606 discloses a tongue and grove profile closure wherein the tongue thickness is less than the width of the groove, and a releasable pressure sensitive adhesive is provided to keep the tongue within the groove. Adhesives, however, are difficult to apply, and may cause undesirable problems by sticking to other bags or surfaces.
Goto et al, U.S. Pat. No. 5,701,996 discloses a specially designed snap-fastener bag having an air evacuation passage along a bottom-seal and a conventional snap fastener along the bag opening. The air evacuation passage has an opening through one side of the bag and a sticky substance is disposed in the passageway to adhere the top and bottom surfaces of the plastic film of the bag after manually evacuating the bag.
Cox, U.S. Pat. No. 5,544,752, and Lambert, U.S. Pat. No. 6,085,906 disclose specially constructed vacuum storage bags having an integrally formed flexible conduit directed through the bag and into the interior of the bag, and sealing strips positioned within or on the exterior of the conduit so that pressure applied to an exterior of the conduit will cause the conduit to collapse and engage the conduit sealing strips and prevent fluid flow through the conduit.
Tretina, U.S. Pat. No. 7,389,629 discloses a portable, hand-operated vacuum pump designed to interface with re-sealable plastic bags that incorporate a simple one-way vacuum value. The disadvantages of this approach are that the system requires users to purchase special re-sealable bags, and the said vacuum valves reduces the amount of available storage volume inside the bags.
Kaufman, U.S. Pat. No. 4,018,253 discloses a vacuum device for freezer bags which includes a hollow retainer member designed to mate with the open end of the bag, and a cap member designed to make an airtight connection with the outside surface of the retainer. A flexible tube extends downwardly through the bottom end of the cap member and upwardly above the cap member, and a valve is provided on the upward part of the tube. The open end of the bag is inserted through the hollow retainer and draped over the top end of the retainer, and the cap is mounted over the top surface of the retainer and the open end of the bag in airtight manner so that the tube passage makes an airtight connection with the interior of the bag. Air is withdrawn from the container through the tube, and the valve on the tube is then closed to close the tube passage.
Others have attempted to overcome problems associated with manually sealing conventional re-sealable bags by providing nozzle attachments that are connected to a household vacuum cleaner hose for evacuating the bag. Such systems require users to handle bulky vacuum cleaners to perform a simple kitchen task.
Brown, U.S. Pat. No. 6,763,857 discloses a vacuum attachment for use with a vacuum hose and a vacuum device, and a conventional plastic food storage bag. The vacuum attachment has one hollow attachment for joining the vacuum attachment to the vacuum hose, and a cylindrical member for inserting the vacuum attachment into the bag. The vacuum attachment may also have an air flow blocker for blocking the air flow between the bag and the vacuum attachment. The air flow blocker is a hollow cylindrical cap with a closed end, and may be equipped with an opening or a filter.
Smith, U.S. Pat. No. 5,873,217 discloses a vacuum sealing method and nozzle adaptor apparatus for sealing a container such as a zipper-type plastic bag. The nozzle adapter has an elongated nozzle end for insertion into the container or bag and a larger vacuum hose for connecting to an existing vacuum source such as household vacuum cleaner. The elongate end of the nozzle is placed in the bag, the bag is sealed as completely as possible around the nozzle, and the vacuum source is turned on. After the air is withdrawn from the bag, the nozzle is quickly removed from the bag and the open portion of the zipper-type seal is quickly engaged before a substantial amount of air can return into the bag.
Lau, U.S. Pat. No. 5,287,680 employs a hand-held battery operated vacuum packing device for evacuating and sealing conventional plastic bags. The device has a housing with a pair of jaws mounted on a lever with a slot between the said jaws and lever through which the edges of the bag are pulled to press the edges together. A nozzle extends outwardly from the housing and an air extractor fan in the housing sucks air from the bag just prior to sealing. With the jaws in an open position, the two mating edges of the bag are threaded together into the slot between the two jaws, and the nozzle is placed in the bag. The lever is then operated to close the jaws. The bag and the vacuum packing device are then pulled in opposite directions, so that the two edges of the bag are pulled past the nozzle and through the slot into sealing engagement with one another. When the bag is nearly completely sealed along its opening, the extractor fan is operated to extract air from the bag through the nozzle. The lever is then released to open the jaws and the nozzle is withdrawn, and the bag manually sealed.
Nguyen, U.S. Pat. No. 7,316,101 attempts to minimize the flow of air back into a sealed plastic bag by depositing a fluid along the seal to improve its leak resistance, and inserting a hollow vacuum tube in the corner of the bag to evacuate the bag. Users manually apply pinching pressure to sandwich the evacuation tube between the unclosed portion of the seal to prevent air from escaping. After a vacuum is drawn in the bag, users must quickly pull out the evacuation tube so that the pinching pressure is transferred to the closure thereby closing the unclosed portion of the seal. This process not only allows air to reenter the bag while the probe is being withdrawn, but also runs the risk of contaminating the contents of the bag with micro-organisms that may be on the probe.
A variety of specially designed large storage bags having air valve arrangements are also known in the art, such as disclosed in Yeager, U.S. Pat. No. 5,829,884 and Koyanagi, U.S. Pat. No. 6,499,600, have been proposed for the purpose of removing air from the storage bags in order to reduce the volume of an item, such as clothing, inside the bag to minimize required storage space.
A variety of combination vacuum and heat sealing devices are known in the art. Most of these types of heat sealing devices are not well suited for conventional re-sealable plastic bags because the heat source typically burns through conventional thin-walled re-sealable bags. Further, such heat-sealing systems are relatively expensive, and their large size prohibits them from being stored in ordinary kitchen drawers.
Accordingly, a need exists for a vacuum sealing system that allows users to vacuum pack the contents of re-sealable flexible plastic bags without experiencing the drawbacks of existing art.
The present invention is distinguished from prior art in general, and these cited patents in particular, by a vacuum sealing method and apparatus that can be used with ordinary re-sealable plastic bags. The system does not require modifying the bags or inserting any type of vacuum probe or adapter into the bags, thereby reducing both cost and complexity while simultaneously improving reliability and ease of use.
The present vacuum sealing method and apparatus for evacuating air from re-sealable plastic bags overcomes the problems with prior art by enclosing the re-sealable bag inside a larger vacuum chamber that evacuates air from the entire system. Further, the system automatically closes the re-sealable bag when the desired vacuum level is reached. This automatic closure feature is very important because once the bag collapses around its contents; the seal becomes immobile, and cannot be moved by hand. The collapsed bag freezes the seal in place whether or not the seal is closed or open. If the seal is not closed, then the vacuum will be lost when the inner bag is removed from the vacuum chamber. Although the sealing action may be accomplished using mechanical devices that feed through the walls of a rigid vacuum chamber, a simpler and more effective approach is to employ a vacuum chamber having flexible walls, and containing apparatus inside the vacuum chamber that automatically performs the sealing operation. A practical way of implementing a flexible vacuum chamber is to employ a larger, flexible re-sealable bag as the vacuum chamber. However, such a system requires preventing the flexible wall of the vacuum chamber from prematurely collapsing around the vacuum port and stopping the vacuum process before reaching the desired vacuum level. The present system prevents such uncontrolled collapse of the flexible vacuum chamber by incorporating a structure inside the vacuum chamber that controls the way the larger bag collapses around the inner bag and vacuum port. This inner structure is referred to as a vacuum tray and incorporates all of the features needed to quickly, reliably, and inexpensively perform the vacuuming and sealing operations. Such features include a vacuum port; a frame that prevents the outer bag from collapsing around the vacuum port; a well that collects fluids that may be forced from the inner re-sealable bag and prevents aspiration of fluids into the vacuuming apparatus; a shelf for sealing the inner re-sealable bag, a ramp that guides the inner bag onto the sealing shelf; components that cause the collapsing outer bag to activate the sealing mechanism of the inner bag; and a means for inexpensively mating the outer bag and vacuum port to external vacuuming apparatus.